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Caption

Polycrystalline silicon solar cell, close-up. This photovoltaic cell converts light into electrical energy. This is a clean and renewable source of energy. The cell is made from a polycrystalline silicon nitride wafer (blue), a semiconductor material, covered by a grid of electrodes. The thinner lines, known as fingers, are made of silver nanoparticles. These collect the current and deliver it to the busbars (horizontal), which direct the current out of the cell. Polycrystalline cells are less efficient than monocrystalline cells, but are far cheaper to manufacture.